Delaware River and Bay Authority

Delaware Memorial Bridge Ship Collision Fender System
DMB Ship Collision - contruction of cell

A History of Excellence

The Delaware Memorial Bridge, spanning the Delaware River, stands as a symbol of remembrance and connectivity. Opening in 1951, it honors the soldiers who severed and scarified in World War II. This iconic structure not only facilitates travel between Delaware and New Jersey but also accommodates marine traffic passing underneath. It's towering structure allows ships, barges, and vessels to navigate the Delaware River, supporting commerce and trade in the region.

DMB Ship Collision - super cell with workers

Project Goals

The Delaware Memorial Bridge Ship Collision Fender System Project aims to enhance the safety and resilience of the iconic bridge against potential maritime incidents. 

Designer of Record

S. T. Hudson Engineers, Inc. is the Designer of Record after the initial design, by another firm, resulted in a minimum bid of $115M. Hudson assisted the DRBA with the CM-GC process to design and re-bid the Delaware Memorial Bridge Collision Protection project. Project totaling $93M.

AASHTO Risk Assessment

Using the proper Risk Assessment standards, Hudson provided a design of the pier protection system to protect against the potential collision of a neo-Panamax vessel.

Key Data Points

Draft Depth
Port Organization Est.
Ships Per Year

Our Team

Want to learn more about our individual expertise? Get to know our team!

Robert Hudson, P.E.

President and Chief Executive Officer
Robert Hudson, P.E. Robert Hudson, P.E.

Robert Hudson, P.E.

President and Chief Executive Officer

Mr. Hudson is a Senior Civil/Structural Engineer with over 40 years of experience in the design and construction of marine facilities. He has special expertise in construction methods and estimating. Over the course of his career, Mr. Hudson has been involved in a wide range of construction activities, with emphasis on marine structures, bridges and pile foundations.

In 2002, Mr. Hudson became President and Chief Operating officer of S. T. Hudson Engineers, Inc and continues to serve in that capacity today. Mr. Hudson is a Registered Professional Engineer in New Jersey, Pennsylvania and Delaware. His professional affiliations include The Ports of Philadelphia Maritime Society; The Deep Foundation Institute; The American Society of Civil Engineers and The National Society of Professional Engineers.

James Thomas

Chief Operating Officer & Vice President
James Thomas James Thomas

James Thomas

Chief Operating Officer & Vice President

Mr. Thomas is Hudson’s Chief Operating Officer and has over 35 years of broad experience in the planning, design, management and execution of marine construction and dredging projects.

Mr. Thomas has worked on projects throughout the United States, the Caribbean, South America and the Middle East. His marine construction and dredging experience includes participation in small to large scale capital works, maintenance and superfund projects. He has managed the construction of offshore ocean ship berthing facilities as well as the construction of harbor berth facilities and terminals.

Leslie (Hudson) Gerhard

Vice President
Leslie (Hudson) Gerhard Leslie (Hudson) Gerhard

Leslie (Hudson) Gerhard

Vice President

Ms. Gerhard is Vice President at S. T. Hudson Engineers, Inc. with over 15 years of experience in marketing, company operations, contract administration, and client relationships. She is responsible for day-to-day office operations, generating and overseeing proposal submissions, marketing efforts, contract administration, team recruitment, and coordination and administration of the summer internship program. In addition, she is involved in developing business among existing clients and new clients which contribute significantly to corporate revenues.

Ms. Gerhard is part of the fourth generation of Hudson family members working in the business, working side by side with her father, Robert S. Hudson, P.E., to lead S. T. Hudson Engineers, Inc.

Anthony DePasquale, P.E.

Vice President & Director of Marine Engineering and Environmental Services
Anthony DePasquale, P.E. Anthony DePasquale, P.E.

Anthony DePasquale, P.E.

Vice President & Director of Marine Engineering and Environmental Services

Mr. DePasquale is a Civil & Geo-technical Engineer with 37 years of experience as a designer, construction manager, negotiator, and permitting consultant with the US Army Corps of Engineers. He specializes in the design, management, and construction of flood protection systems, bulkhead rehabilitation, and waste and dredge disposal containment facilities.

In addition, he has reviewed and negotiated numerous construction contract claims, permitting issues, and engineering disputes. Mr. DePasquale's experience has given S.T. Hudson valuable insight into the permitting process and environmental impact assessments from the viewpoint of the USACE and other regulatory agencies.

William Jenkins

Vice President & Director of Marine Services
William Jenkins William Jenkins

William Jenkins

Vice President & Director of Marine Services

Mr. Jenkins has 17 years of experience and a comprehensive knowledge of various hydrographic technologies and methods.

Recently, Mr. Jenkins has applied his talents to implementing various multibeam hydrographic surveys for ship navigation safety, object detection, clearance surveys, sediment transfer surveys, pre- and post-dredge surveys, and bridge inspection scour monitoring.

Project Details

S. T. Hudson Engineers, Inc. assisted the DRBA with the CM-GC process to design and re-bid the Delaware Memorial Bridge Collision Protection project. 

The design was required after another design, completed another firm, resulted in a minimum bid of $115M. The design and rebid process included engaging six (6) contractors from the original bidding process and evaluating the contractors based on qualifications and project approach. Under very tight time constraints, Hudson provided complete design plans and specifications to the selected contractor for pricing. Hudson then worked with the Independent Cost Estimator to evaluate the selected contractors’ bid and engage in value engineering to make sure the project goals were reached within the designated budget. Once Hudson completed the design for the project and the CM-CG process, the DRBA saved nearly $25M. The savings were realized by eliminating dredging of the material in the cells, utilizing wick drains to speed consolidation of existing sediments, and reducing the overall amount of steel and concrete required in the final configuration. The protection system represents one of the largest free standing cell structure projects ever built.  In addition, Hudson acquired permit extensions and modifications from USACE and DNREC which enabled construction of the trestle bridge, another cost saving component of the project. Hudson reviewed all submittals for materials, design of intermediate structures, and participated in Contractor design modification review.

The design includes the construction of eight (8) steel cells, filled with sand and capped with concrete and rock. The strategically placed cells are designed to AASHTO standards with the intention of stopping or deflecting a neo-Panamex size container vessel, over 1000 feet in length, from hitting the bridge piers. An extensive risk assessment was performed to capture all of the possible scenarios and angles of a potential ship strike. Each cell measures 80 feet in diameter and their construction, involves driving up to 135 feet long steel sheet piles 80-90 feet into the river bottom.

Hudson participated in the review of the test pile program to verify the designs, as well as participating in the Construction Management and monitoring phase of the project with the Authority’s construction manager.

Scope of Services

  • Engineer of Design
  • Feasibility Study with several options for the protection system.
  • Obtained permits from DENREC & USACE
  • Expedited Design build CM-GC process to meeting to meet schedule and budget
  • Engineering and Design Plans
  • AASHTO risk assessment.
  • Total Installed Cost Estimates and Schedules.
  • Hydrographic Surveys

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